Polyolefin-based resins are relatively inexpensive and excellent in e.g., moldability, heat resistance, solvent resistance, mechanical properties and appearance. Because of this, polyolefin-based resins are processed into various types of compacts and used in a wide variety of fields. For example, a composition containing such a polyolefin-based resin is formed into a mold by extrusion molding and used as e.g., a deck material. The polyolefin-based resins are also excellent in quake resistance. Because of this, polyolefin-based resins have been recently increasingly used as e.g., gas pipes and water pipes.
As an example of a compact using a polyolefin-based resin, a polyolefin-based resin pipe is disclosed in Japanese Patent Laid-Open No. 2006-327154 (Patent Literature 1).
To enhance strength, a glass fiber is sometimes used in compacts. As an example of a compact using a glass fiber, a fiber-reinforced synthetic resin pipe having a cylindrical shape is disclosed in Japanese Patent Laid-Open No. 2007-216555 (Patent Literature 2). This pipe has a plurality of fiber-reinforced resin layers and fiber-reinforced resin layers are laminated in the circumferential direction of the cylinder. The fiber-reinforced resin layer has a glass fiber-reinforced resin layer, which is formed of a glass fiber and a synthetic resin, and an organic nonwoven fabric layer, which is formed of an organic nonwoven fabric and a synthetic resin.
International Publication No. WO02/28971 (Patent Literature 3) discloses a compact using a polyphenylene-based composite resin composition containing a glass fiber or an inorganic filler. The polyphenylene-based composite resin composition contains a polyphenylene ether (20 to 98 wt %), at least one type of resin (1 to 40 wt %) selected from the group consisting of a polystyrene, a polyphenylene sulfide, a polyether imide, a polycarbonate and a polyethylene (including HDPE, LDPE, LLDPE, VLDPE) and a glass fiber or an inorganic filler (1 to 40 wt %).
In piping systems conventionally used, the entire system is constituted basically by connecting pipes of a similar type, as is described, for example in Japanese Patent Laid-Open No. 2010-243129 (Patent Literature 4). Connecting pipes of different types is sometimes unavoidable in the case where e.g., lineup of ready-made pipelines and cost are limited; however, connecting heterogenous pipes is very difficult and extremely disadvantageous. In contrast, connecting homogenous pipes is easy and mechanical properties become equivalent. Likewise, the homogenous pipe connection has great advantages and thus has been actively employed.